PTL 1 discloses a voice command input device including a plurality of voice input units. When a plurality of voices are input, the voice command input device prioritizes the plurality of voices, and recognizes one voice with the highest priority.
FIG. 6 is a block diagram showing a configuration of the voice command input device disclosed in PTL 1.
The voice command input device includes a plurality of microphones 601 which are voice input units. Controller 602 recognizes control content specified by voice, and controls the operation of a connected appliance based on the recognized control content. FIG. 6 shows an example where controller 602 performs switching between on and off of power of air conditioner 610, or switching between on and off of power switch 612 of lighting equipment 611.
Microphone 601 is installed in each room of a house, and is connected by a signal wire to one controller 602 installed in the house. In the case where a speaker instructs by voice that switching between on and off of power of air conditioner 610 is to be performed, controller 602 transmits, from interface 607 to remote control 608 of air conditioner 610, based on the result of voice recognition, a control signal instructing that switching between on and off of power is to be performed. Then, the power of air conditioner 610 is turned on or off via remote control 608.
In the case where a speaker instructs by voice that switching between on and off of power of lighting equipment 611 is to be performed, controller 602 transmits, from interface 607 to signal conversion circuit 609, a control signal (digital signal) instructing that switching between on and off of power is to be performed. Signal conversion circuit 609 converts the received control signal into an analog signal and transfers the analog signal to lighting equipment 611, and power switch 612 of lighting equipment 611 is turned on or off.
Controller 602 is configured in the following manner. Controller 602 includes analog/digital conversion circuit (hereinafter referred to as “A/D circuit”) 603, arbitration circuit 605, processor 606 for voice recognition, and interface 607.
A/D circuit 603 converts an analog voice signal that is input from microphone 601 into a digital voice signal. Controller 602 is provided with the same number of A/D circuits 603 as the number of microphones 601 installed in the house.
Arbitration circuit 605 accepts only the earliest received voice signal among voice signals input from the plurality of A/D circuits 603. That is, arbitration circuit 605 detects microphone 601 to which voice is input earliest, and connects signal line 604 of this microphone 601 to processor 606 for voice recognition. For example, arbitration circuit 605 can detect the earliest input voice signal by comparing the rise of pulses of the voice signals.
In this manner, only the voice that is uttered earliest by a speaker is recognized by processor 606 for voice recognition. Signals of voices that are uttered later by other speakers reach only arbitration circuit 605, and are not recognized at processor 606 for voice recognition.
As described above, with the voice command input device disclosed in PTL 1, only the voice that is uttered earliest is recognized by processor 606 for voice recognition, and voices that are uttered later are not recognized.
However, sometimes it is not desirable that a voice is not recognized just because it was uttered later. For example, in a case where one voice command input device is used by a plurality of users, voices of the plurality of users picked up by a plurality of microphones are desirably each recognized and processed without prioritization.